4 Instances Where the Keto Diet May Be Helpful, According to Research

The keto diet isn’t for everyone, but it still may have a place in these health conditions.

Reviewed by Dietitian Emily Lachtrupp, M.S., RD

While the keto diet may fall toward the bottom at No. 25 in the U.S. Health and News Report’s Best Diets Overall category for 2024, it’s still trending. In fact, that same report ranked the ketogenic diet as No.1 when it comes to fast weight loss. The plan involves eating at least 70% of your calories from fat, and when done correctly, puts your body into ketosis, or a state where it burns fat for energy rather than glucose.

But hang tight before hopping on the keto diet. While it may seem like a good choice if you’re looking to lose weight, it’s often not recommended by nutrition experts—except in specific cases. Read on to find out the instances where the keto diet may offer benefits, and what you need to know before considering this diet type for yourself.

Related: Ketogenic Diet 101: A Beginner's Guide

The History of the Keto Diet

The ketogenic diet—keto for short—is a high-fat, moderate-protein, very-low-carbohydrate way of eating. According to a past review in Epilepsia, the ketogenic diet was developed during the 1920s as a treatment for epilepsy, a neurological disease that causes seizures. Physicians jumped on board and found that by restricting carbohydrate intake and focusing on fat and some protein, patients experienced seizure relief in two to three days. However, advances in antiepileptic drugs took the diet out of the spotlight for decades.

Things changed in 1994 when a popular television show ran a special on the keto diet as a form of treatment for epilepsy, leading to the resurgence of the diet. Since this series, research has expanded and more studies have investigated the use of the ketogenic diet in treating specific conditions—including for supporting weight loss. Decades later, the keto diet reached peak popularity, being crowned the most Googled diet in the U.S. in 2020, according to a 2022 review in Missouri Medicine.

4 Conditions Where the Keto Diet May Be Worth Considering

Epilepsy

Given the fact that the diet itself originated in the early 20th century as a form of treatment for seizure control, the keto diet remains a form of treatment for epilepsy. “The most studied condition that the keto diet may benefit is for people with epilepsy. Some research shows that those who follow the keto diet may see a decline in the number of seizures by half,” says Roxana Ehsani, M.S., RD, a registered dietitian nutritionist and board-certified sports dietitian. “The high-fat diet proves to be a fuel for the brain and acts as an anticonvulsant,” she says.

Epilepsy can be very challenging for a patient to manage without proper treatment, and even then, oftentimes pharmaceutical drugs don’t completely halt the seizures, leading to the need for other strategies, such as the keto diet. A 2019 review in Frontiers in Neuroscience concluded that the ketogenic diet can be a valuable form of treatment for epileptic patients, regardless of age, to control their seizures. However, researchers also noted that the classic ketogenic diet, which consists of 90% fat, can be very challenging to follow without a tailored plan and a team approach. Thus, more research is needed on the forms of ketogenic diet available and how to properly train health care professionals to support patients in following this diet and avoiding nutrient deficiencies.

Weight Management

There is no question that the keto diet is a popular way to lose weight. While a 2020 review in the Journal of Nutrition discussed the potential benefits for the keto diet when it comes to managing obesity and type 2 diabetes, the clinical research isn’t quite there yet. Plus, there are still unanswered questions, like the cardiovascular effects of raising LDL cholesterol with high fat intake. And while it may produce quick results, the diet is often difficult for people to sustain long-term. “While the keto diet is widely popular as a way to reduce body fat and/or lose weight, long-term studies have not found the keto diet to be more beneficial than calorie-controlled meal plans for weight loss long-term,” says Erin Palinski-Wade, RD, CDCES, author of Belly Fat Diet for Dummies.

Type 2 Diabetes

While following a low-carbohydrate diet is not a new recommendation for someone with type 2 diabetes, the increased interest in the keto diet—which not only emphasizes low-carb, but also high-fat—is.

One of the potential benefits is that the keto diet may help people with diabetes decrease their hemoglobin A1C (HbA1c), which is a measure of average blood sugar over the past two or three months, according to a 2021 review published in Nutrients. Some research has shown that these very-low-carb diets have been able to help people reduce the amount of medication, like insulin, they need to take.

And the diet has the potential to work rather fast. A very small study in the Journal of Diabetes Research in 2019 followed 11 female participants with type 2 diabetes over a 90-day period where they were limited to consuming less than 30 grams of carbohydrates per day. At the start, their average A1C was 8.9% (with above 6.5% being the range for a diabetes diagnosis), but after three months, their average level had dropped to 5.6% (anything less than 5.7% is considered normal), reversing their diabetes diagnosis during the study. With this said, we have to emphasize that this intervention was small and short-term. “While some research has suggested that the keto diet may be helpful for people with diabetes, this is preliminary research, so take it with a grain of salt,” says Ehsani.

Alzehimer’s Disease

Rates of dementia and Alzehimer’s disease continue to rise, according to a 2023 Alzheimer’s Association Report. That’s one reason why exploring the connection between diet and brain health is so important.

When it comes to keto, short-term trials, such as one published in Alzheimer’s & Dementia in 2018 have investigated the use of the diet as a potential treatment for Alzehimer’s. The researchers found cognitive improvements over a three-month period. However, after a one-month period where people returned to their normal diet, the benefits disappeared and participants’ cognition reverted to baseline. The production of ketones in a keto diet may provide an alternate fuel source for the brain, which may impact brain health, points out a 2022 narrative review in AIMS Public Health. Of course, more research is needed.

It’s worth pointing out that the common ketogenic diet may be high in saturated fat, the type of fat that may not be beneficial for the brain. Thus, if the keto diet is to be used to offer cognitive benefits for those with Alzehimer’s disease, it needs to be a well-designed keto diet with an emphasis on the good-for-you fats like omega-3 fatty acids and unsaturated fats.

Related: What Is Keto 2.0? Pros & Cons, According to Health Experts

Considerations and Precautions for the Keto Diet

While the keto diet may seem like a sure bet, especially for those who want a quick fix for weight loss, it is not everything it’s cracked up to be. In fact, the only long-term research available supporting use of the keto diet is in epilepsy.

Given this, Palinski-Wade and Ehsani want to make you aware of the following points:

• Research has not found a ketogenic diet to be a better choice for weight management than a well-balanced, calorie-controlled diet.

• A poorly planned keto diet can increase intake of saturated fats, which in turn may raise inflammation and cholesterol levels, as well as potentially worsen insulin resistance.

• Following a strict keto diet can lead to nutrient deficiencies and imbalance without careful planning and monitoring. Supplementation may be necessary.

• Constipation may occur during keto, since it’s very difficult to eat enough fiber-rich foods.

• You may experience the keto flu during the first few days or even weeks of starting the diet as your body adjusts to being fed less carbs. Although you might not have the actual flu, you may still feel lousy with headaches, fatigue, irritability and nausea.

With this in mind, collaborating with a health care team is the best way to design a healthy eating plan that will work for you, whether that’s keto or not. If you plan to try the keto diet and have one of these conditions, a registered dietitian can help guide you on:

• Increasing dietary fiber

• Monitoring saturated fats

• Incorporating unsaturated fat sources, like nuts, seeds, olive oil and fish

• Increasing water intake

• Evaluating nutrient intakes to decide if you need to supplement

The Bottom Line

Research has shown the keto diet may offer benefits for people who have been diagnosed with epilepsy. However, it may be useful for weight management, type 2 diabetes and Alzheimer’s disease, though more clinical research is needed. The keto diet requires a big commitment, and many people aren’t able to stay on it. “Following a diet that restricts whole food groups can be very hard to maintain and usually will not lead to long-term compliance or benefits,” Palinski-Wade says. While more research is needed on the long-term health impacts of following a keto diet, there is plenty of research detailing the pitfalls of restrictive dieting, mainly that it’s very difficult to achieve sustainable weight loss if you’re too restrictive. For a more sustainable and well-balanced option, check out the 80/20 diet and focus on small, buildable changes.

Read the original article on Eating Well.